Perforation apparatus of the tobacco processing industry for perforating a wrapper of a rod-shaped article

ABSTRACT

A perforation apparatus of the tobacco-processing industry for perforating a wrapper of a rod-shaped article includes at least one optical radiation source to generate at least one primary beam. Optical elements are operative to split the at least one primary beam into at least four mutually non-overlapping partial beams to produce at least four perforation zones offset in an axial direction of the rod-shaped article. Partial beams arranged mirror symmetrically to each other with respect to a mirror plane of the rod-shaped article are derived from the same primary beam.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of German Application No. 10 2006 013 929.1 filed Mar. 21, 2006, the subject matter of which is incorporated herein by reference, together with each and every U.S. and foreign patent and patent application mentioned below.

BACKGROUND OF THE INVENTION

The invention concerns a perforation apparatus of the tobacco-processing industry for perforating a wrapper of a rod-shaped article, having at least one optical radiation source for generating at least one primary beam, and optical elements for splitting the primary beam into mutually non-overlapping partial beams for producing perforation zones offset in the axial direction of the rod-shaped article.

Perforation apparatuses for producing a perforation zone in the tipping paper of a filter cigarette are known from German patent documents DE 33 21 800A1, DE 34 18 188A1, DE 37 05 627A, DE 195 30 216 A1 and DE 101 60 167 A1, and European patent document EP 0 578 385 A1. Usually, these apparatuses for perforating tipping paper are used in the manufacture of double-length cigarette rods. Therefore, it is known in the art to split the primary beam into two partial beams for producing identical perforations for each half of a double-length cigarette rod corresponding to one cigarette.

SUMMARY

It is an object of the present invention to provide a perforation apparatus that allows differentiated influencing of the air permeability through the perforation in the wrapper of the rod-shaped article.

The above and other objects are achieved according to the invention, wherein in one embodiment there is provided a perforation apparatus of the tobacco-processing industry for perforating a wrapper of a rod-shaped article, comprising: at least one optical radiation source to generate at least one primary beam; and optical elements operative to split the at least one primary beam into at least four mutually non-overlapping partial beams to produce at least four perforation zones offset in an axial direction of the rod-shaped article, wherein partial beams arranged mirror symmetrically to each other with respect to a mirror plane of the rod-shaped article are derived from the same primary beam.

On account of the production of at least four independent partial beams, instead of the conventional production of two independent partial beams, at least two independent perforation zones can be produced in the tipping paper for each cigarette. This allows individual adjustment of the air permeability of the wrapper at several axially offset positions. This is especially important in connection with the development of cigarette filters of multi-stage construction, to allow individual adjustment of the air permeability of the tipping paper for each filter component.

Due to the allocation of partial beams arranged mirror symmetrically to each other, with respect to a mirror plane of the rod-shaped article, to the same primary beam, an identical perforation structure of the two cigarettes of a double-length cigarette rod is ensured. This feature is different from the disclosure of German patent document DE 33 21 800 A1, which provides an asymmetrical allocation of the partial beams to the primary beams, with respect to the mirror plane of the rod-shaped article, which is contrary to the aim of providing identical perforations for each cigarette of a rod-shaped article in the form of a double length cigarette.

According to the above described embodiment of the invention, at least four mutually non-overlapping partial beams are generated. This means that the bundles of light beams of at least four partial beams do not overlap each other geometrically in the region between the optical elements and the rod-shaped article. This allows individual, independent adjustment of the perforation properties produced by each partial beam, in particular the production of different perforation zones for a cigarette.

The generation of four partial beams is known, for example, from German patent documents DE 3418188A1, DE 19530216A1 and DE 10160167A1. However, in each case two partial beams for producing a uniform perforation zone for a cigarette overlap. Each perforation zone therefore includes two separate, but closely spatially connected rows of perforations. These documents therefore disclose only two partial beams or partial beam regions which do not overlap each other.

Within the scope of the present application the term “perforation zone” is used for all perforations which are produced with partial beams overlapping each other. According to the invention, therefore, at least four perforation zones (at least two perforation zones per cigarette) are produced, while the above-mentioned documents disclose the production of only two perforation zones (one perforation zone per cigarette).

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described below with the aid of advantageous practical examples with reference to the attached drawings.

FIG. 1 shows a perforation apparatus in a first embodiment in a view perpendicular to the longitudinal axis of the rod-shaped article.

FIG. 2 shows the perforation apparatus of the first embodiment in a view along the longitudinal axis of the rod-shaped article.

FIG. 3 shows a perforation apparatus in a second embodiment in a view perpendicular to the longitudinal axis of the rod-shaped article.

FIG. 4 shows the perforation apparatus of the second embodiment in a view along the longitudinal axis of the rod-shaped article.

FIG. 5 shows a perforation apparatus in a third embodiment in a view perpendicular to the longitudinal axis of the rod-shaped article.

FIG. 6 shows a perforation apparatus in a fourth embodiment in a view perpendicular to the longitudinal axis of the rod-shaped article.

DETAILED DESCRIPTION

In the embodiment in FIGS. 1 and 2, the perforation apparatus 10 includes a beam generating device 11, preferably a laser, for generating an optical primary beam 12. Optical elements 13 to 16 split the primary beam 12 into partial beams (secondary beams) 17 to 20 and deflect the partial beams 17 to 20 in a direction towards a rod-shaped article 21. Corresponding focusing elements 24 to 27 focus the partial beams 17 to 20 on the rod-shaped article 21 to produce corresponding perforations 28 to 31 in the tipping paper 32 of the rod-shaped article 21. The rod-shaped article 21 is in the form of a double-length cigarette, i.e. it has two halves 22, 23 each forming one cigarette. The rod-shaped article 21 is cut into two single cigarettes 22, 23 in the mirror plane S in a subsequent production process.

To produce the perforation, the laser radiation is pulsed, for example by a chopper disc, not shown, and the rod-shaped article 21 is rotated about its longitudinal axis at a fixed location. This takes place preferably by a corresponding rolling device in a filter assembler, as disclosed, for example, in German patent document DE 37 05 627 A1, particularly reference being made to FIG. 1 thereof and its description, wherein there is shown and described a filter assembler apparatus 36 that includes a perforation apparatus 10.

Referring again to FIG. 1 of the present application, the optical elements 13 to 15 are beam splitters in the form of semi-transmitting mirrors which each reflect a portion of the primary beam 12, resulting in the partial beams 17 to 19, and let through the remainder of the primary beam 12 to the subsequent optical element 16 to produce the partial beam 20. The last optical element 16 as a rule has a reflectivity of 100% (non-transmitting mirror or purely deflecting element). FIG. 2 shows the perforation apparatus of the FIG. 1 in a view along the longitudinal axis of the rod-shaped article

The partial beams 17 to 20 are extended beams, as illustrated by the example of the partial beam 17 in FIG. 1. For the other partial beams 18 to 20, only the light cone behind the respective focusing lenses 25 to 27 has been shown. As can be seen from FIG. 1, the four beams behind the optical elements 13 to 16 are free from overlap with each other.

If the optical elements 13 to 15 successively have a reflectivity of 25%, 33% and 50%, each of the partial beams 17 to 20 has the same intensity, so that identical perforations 28 to 31 are produced. However, this does not necessarily have to be the case. In general, the reflectivity of the optical elements 13 to 15 must only be coordinated with each other such that in each case mirror symmetrical partial beams have the same intensity, with reference to the mirror plane S between the cigarettes 22 and 23, thus ensuring that the two cigarettes 22 and 23 have the same perforation structure. For example, the partial beams 17 and 18 can have different intensities in order to be able to individually adjust the air permeability of the perforations 28 and 29 of the cigarette 22, the sum of intensities of the partial beams 17 and 18 in this case being appropriately 50%.

In the embodiment according to FIGS. 3 and 4, the perforation apparatus includes two beam generating devices 11A, 11B, in particular two lasers, for generating two optical primary beams 12A and 12B. The optical elements 13 and 16 are located in the beam path of the primary beam 11A, and the optical elements 14 and 15 are located in the beam path of the primary beam 11B. In other words, the mirror symmetrical outer partial beams 17 and 20 are allocated to the same primary beam 12A, and the inversely symmetrical inner partial beams 18 and 19 are allocated to the same primary beam 12B. The use of two individually adjustable beam generating devices 11A, 11B to generate separate primary beams 12A, 12B allows the perforation properties, for example the number of holes or the ventilation, of the outer perforations 28, 31 to be individually adjusted independently of the perforation properties of the inner perforations 29, 30.

FIG. 4 shows the perforation apparatus of FIG. 3 in a view along the longitudinal axis of the rod-shaped article. As can be seen from FIG. 4, the optical assembly 11A, 13, 16, 24, 27 corresponding to the first primary beam 12A is expediently offset by an azimuth angle ω from the optical assembly 11B, 14, 15, 25, 26 corresponding to the second primary beam 12B. In this case a low azimuth angle ω is preferred with a view to a compact size.

The beam splitters 13 and 14 in this embodiment expediently have a reflectivity of 50%.

In a modified embodiment, a plurality of primary beams can also be generated by a single beam generating device, for example a use of one or more pre-arranged beam splitters.

FIG. 5 shows a view of another embodiment along the longitudinal axis of the rod-shaped article similar to the view shown in FIG. 4. Two rows of perforations 28A, 28B or 31A, 31B are produced in each of the two outer perforations zones 28, 31 of each cigarette 22, 23, so that there is a total of six rows of perforations, including the two inner perforation zones 29, 30. For this purpose the primary beam 12A is split into two primary beams 33, 34. This can be done for example by a diffractive element 35, or some other suitable device, for example an arrangement as described in German patent document DE 195 30 216 A1. The primary beams 33, 34 are partially reflected by the beam splitter 13 in order to generate the partial beams 17A, 17B which in turn produce the rows of perforations 28A, 28B. The primary beams 33, 34 transmitted by the beam splitter 13 are reflected by the beam splitter 16 in order to generate the partial beams 20A, 20B which in turn produce the rows of perforations 31A, 31B.

The light beams or cones corresponding to the partial beams 17A, 17B overlap spatially, as can be seen from FIG. 5 by the example of the light cones corresponding to the partial beams 17A, 17B after the focusing element 24. Similarly, the light beams or cones corresponding to the partial beams 20A, 20B overlap. The embodiment of FIG. 5 therefore includes four perforation zones corresponding to four mutually non-overlapping partial beam regions 17 to 20 with a total of six partial beams 17A, 17B, 18, 19, 20A, 20B.

In a further embodiment, alternatively or in addition in each of the inner perforation zones 29, 30 a plurality of rows of perforations can be produced.

The invention is not restricted to producing two rows of perforations per perforation zone.

The embodiment according to FIG. 6 shows that the optical beam splitting means are not restricted to semi-transmitting mirrors and that a separate optical beam splitting device does not have to be provided for each independent partial beam. Here optical prisms 40, 41 made of a suitable material, for example ZnS, are provided as the beam splitting mechanism. The mutually independent partial beams 17 to 20 are here produced by reflection at the front and rear sides of the prisms 40, 41.

The distance from the inner perforation zones 29, 30 to the mirror plane S is preferably within the range from about 11 to about 15 mm and is further preferably approximately 13 mm, and the distance from the outer perforations zones 28, 31 to the mirror plane S is preferably within the range from about 19 to about 25 mm.

The partial beams 17 to 20 are preferably incident on the wrapper of the rod-shaped article 21 at an angle of not more than 10°.

The invention has been described in detail with respect to referred embodiments, and it will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the appended claims, is intended to cover all such changes and modifications that fall within the true spirit of the invention. 

1. A perforation apparatus of the tobacco-processing industry for perforating a wrapper of a rod-shaped article, comprising: at least one optical radiation source to generate at least one primary beam; and optical elements operative to split the at least one primary beam into at least four mutually non-overlapping partial beams to produce at least four perforation zones offset in an axial direction of the rod-shaped article, wherein partial beams arranged mirror symmetrically to each other with respect to a mirror plane of the rod-shaped article are derived from the same primary beam.
 2. The perforation apparatus according to claim 1, further including a device following the optical radiation source which is operative in combination with the optical elements to generate from the at least one primary beam overlapping partial beams to produce a plurality of rows of perforations in respective perforation zones.
 3. The perforation apparatus according to claim 1, wherein the at least one optical radiation source generates at least two independent primary beams.
 4. The perforation apparatus according to claim 3, wherein the optical elements include at least a first optical element in a beam path of one of the independent primary beams and a second optical in a beam path of a second one of the independent primary beams, and the first and second optical elements are offset by an azimuth angle about the rod-shaped article.
 5. The perforation apparatus according to claim 4, wherein the azimuth angle is less than about 60°.
 6. The perforation apparatus according to claim 4, wherein the azimuth angle is less than about 45°.
 7. The perforation apparatus according to claim 4, wherein the azimuth angle is less than about 30°.
 8. The perforation apparatus according to claim 3, wherein the at least one optical radiation source comprises separate optical radiation sources to generate each primary beam.
 9. The perforation apparatus according to claim 1, wherein the optical elements include partially transmitting mirrors.
 10. The perforation apparatus according to claim 1, wherein the optical elements have transmittances that are co-ordinated with each other so that, with respect to a mirror plane of the rod-shaped article, two partial beams arranged mirror symmetrically to each other each have substantially equal radiation intensity.
 11. A filter assembling machine, comprising an apparatus for rotating a rod-shaped article about a longitudinal axis of the rod-shaped article in a stationary perforation position forming a combination with a perforation apparatus according to claim 1, for perforating a rod-shaped article rotating in the perforation position.
 12. A method for perforating a wrapper of a rod-shaped tobacco article, including steps of: generating at least one optical primary beam; splitting the primary beam into at least four mutually non-overlapping partial beams, wherein partial beams arranged mirror symmetrically to each other, with respect to a mirror plane of the rod-shaped article are derived from the same primary beam; and perforating the rod-shaped article in at least four perforation zones offset in an axial direction of the rod-shaped article by the partial beams. 